Repair your roof if the damage is localised, the roof is within its expected lifespan and the structure underneath is sound. Consider replacement if the roof is beyond 50–60 years old with failing underlay, if leaks keep appearing in different places, if the roofline is sagging, or if repair costs are approaching a third of the price of a new roof. An honest roofer will show you photos and tell you which applies.
Key takeaways
- Most Surrey roofs need repairs, not replacement — be wary of anyone who says otherwise without evidence.
- Clay tiles and natural slate can last 60–100+ years; the underlay and fixings beneath them often fail first.
- Leaks appearing in several different places usually point to failed underlay.
- A sagging roofline is structural and needs looking at promptly.
- Large re-roofing work normally needs Building Regulations sign-off.
How long should a roof last?
Surrey's housing stock ranges from medieval cottages in Shere to Victorian villas in Guildford and Godalming, inter-war semis in Woking and modern estates in Merrow and Burpham. Expected lifespans vary a lot by material:
| Material | Typical lifespan | Common in |
|---|---|---|
| Natural slate | 80 – 100+ years | Victorian & Edwardian homes |
| Hand-made clay tiles | 60 – 100 years | Surrey villages, Arts & Crafts houses |
| Concrete tiles | 40 – 60 years | 1950s onwards |
| Traditional bitumen underlay | 40 – 50 years | Beneath most pre-2000 roofs |
| Felt flat roof | 10 – 20 years | Older extensions & garages |
| EPDM / GRP flat roof | 20 – 30+ years | Modern flat roofs |
Notice that the tiles often outlast what's underneath them. On many 1930s–1960s Surrey homes the tiles are fine, but the nails, battens and underlay have reached the end of their life.
9 signs your roof may need replacing
- Leaks in more than one place. One leak is a repair. Leaks that move around are a symptom of failed underlay.
- Daylight in the loft. Pinpricks of light through the roof covering mean water can get in the same way.
- A sagging or wavy roofline. Stand across the road and look along the ridge. Dips suggest weakened battens or rafters.
- Widespread slipped slates ("nail sickness"). When the fixings corrode, slates start sliding out across the whole roof rather than in one spot.
- Crumbling or "blown" tiles. Tile faces flaking off after frost means they are absorbing water.
- Brittle, torn underlay visible from inside the loft.
- Damp, mould or rot in roof timbers.
- Heavy moss with tiles lifting. Moss alone isn't a reason to re-roof, but it holds moisture and can lift tiles.
- You're repairing it every winter. If the annual repair bill keeps climbing, the maths starts to favour replacement.
When a repair is the right call
In our experience the majority of roofs we're called to across Guildford, Farnham, Cranleigh and Dorking need a repair, not a replacement. A repair is usually right when the damage is confined to one area (storm damage, a failed flashing, a cracked valley), the roof is comfortably within its expected lifespan, and the timbers and underlay are sound. If someone recommends a full new roof, ask to see photographic evidence of why.
What a full re-roof involves
A typical re-roof means scaffolding the property, stripping the old covering, inspecting and repairing timbers, fitting modern breathable membrane and new treated battens, then re-tiling — either with new materials or, on period homes, by salvaging and re-using the sound original tiles or slates. New lead work, ridges and verges complete the job. Most houses take one to two weeks depending on size and weather.
Replacing a large proportion of a roof covering is normally notifiable under Building Regulations, and you may be required to upgrade loft insulation at the same time. In conservation areas and on listed buildings — common in central Guildford, Shere, Ripley and Haslemere — materials generally need to match the originals. We handle all of this as part of the job.
See our roof replacement service for more detail, or the repair cost guide if you think a repair will do.
Frequently asked questions
How do I know if my roof needs replacing or just repairing?
How long does a roof last in the UK?
Do I need planning permission or Building Regulations for a new roof?
Can I reuse my existing tiles or slates?
Written by the Alpha Same Day Roofing team. Checkatrade-approved roofers with over 20 years’ experience repairing and replacing roofs across Guildford, Surrey and London. This guide is general advice — every roof is different, so please book a free inspection for advice specific to your property.
